commgrp@silver.bacs.indiana.edu (BACS Data Communications Group) (10/18/89)
to sci.electronics and rec.ham-radio: _Sky & Telescope_ October '89 published plans for a "Jam-jar magnetometer" useful as an aurora alarm. A more advanced version of the same device appeared in the July 1988 issue of _The Lowdown_ (newsletter of the Longwave Club of America). This one has a Hall- effect sensor and amplifiers added, so that the compass deflections can be output to a chart-recorder. See also _Electronics_ magazine, December 1980, p. 112 for plans of a Hall-effect magnetic compass with no moving parts. Copies of the above available for SASE, and I'm sending them to WA4VLV re his request on rec.ham-radio. -- Frank Reid W9MKV @ K9IU reid@gold.bacs.indiana.edu P.O. Box 5283 Bloomington. Indiana USA 47407-5283